1. Field of the Invention
The present invention relates to data interfaces, and more particularly to data interfaces for integrated-services digital network communication systems.
2. Description of the Prior Art
Data interfaces are provided in integrated-services digital network (ISDN) communication systems for the connection of data terminal equipment to the communication systems. These data terminal equipment and, consequently, the communication systems predominantly comprise V.24 interfaces. The physical and procedural properties of the V.24 interface correspond to the V.24 recommendation standardized by the CCITT (Comite Consultatif International des Telegraphique et Telephonique). The data exchange between data terminal equipment and data transmission equipment or, respectively, a communication system occurs via a V.24 interface. In communication systems, particularly in public or private switching equipment, the V.24 interface is realized directly at the switching equipment or in remote communication adapters. Two data terminal equipment connected directly to the communication system or to the appertaining communication adapters are switched by automatic or manual call set-up procedures with the assistance of the switching equipment or, respectively, are connected to one another for the purpose of a data exchange. The automatic call set-up procedure is implemented via interface circuits provided for this purpose and the manual call set-up procedure can be implemented with the assistance of push button sets arranged in the data terminal equipment, or separate peripheral equipment.
Furthermore, communication systems or, respectively, switching equipment, frequently comprise a V2.4 data interface for the connection of administration and maintenance terminal equipment. The administration and maintenance functions, such as, for example, changes of authorization, selection procedures, and transmission rates for the individual subscriber terminals, are realized with the assistance of the administration and maintenance terminal equipment. In addition, the error recognition and error localization procedures are controlled with the administration and maintenance terminal equipment.
A test of these interfaces is usually implemented in such a manner that a respective testing device is connected to, for example, two data interfaces realized by V.24 interfaces and a connection to another testing device is set up by a testing equipment. Subsequently, information from one testing device are transmitted via two data interfaces and the switching system to the other testing device, and the received information are checked with respect to occurring errors. The corresponding administration and maintenance measures and settings are effected by a further testing device connected to the V.24 administration and maintenance interface. To this end, a corresponding test program or, respectively, user program is required in each of the testing devices and is realized, for example, by a personal computer or a data terminal. Since only one V.24 interface can be constantly controlled or, respectively, sampled with the traditional personal computers or, respectively, terminals, a personal computer or, respectively, a data terminal must be provided for each V.24 interface, even though a plurality of V.24 interfaces are present for the connection of different data equipment, such as, for example, printers, data transmission equipment, etc.